Ieans for poising the hasr-springs of watches



(No Model.)

' T. GRIBI.

MEANS FOR POISING THE HAIR SPRINGS OP WATCHES.

Patented July 20, 1886.

UNITED STATES PATENT OFFICE.

THEOIHILUS GRIBI, OF ELGIN, ILLINOIS.

WEANS FOR POlSiNG THE HAlR-SPRINGS OF WATCHES QPTSCIE'ICATION forming part of Letters Patent No. 345,840, dated July 20,1886.

Application filed November 18, 1885. Serial No. 193,233. (No model.)

To aZZ whom it may concern.-

Be it known that l, THEOIHILUS GRIBI, of Elgin, in the county of Kane and State of Illinois, have invented a new and useful Improvement in Means of Poising the Hair- Springs of atches and Clocks, of which the following is specification.

By experiments with watches and clocks it is found that thcreis a veryconsiderable variation in the rate of the watch or clock when runningin avertieal position as when a watch is carried in the pocket. This difference or variation exists even when the balance-wheel itself is perfectly poised, so that the center of weight is exactly coincident with its axis, and is due wholly or in great degree to the lack of perfect poise in the hair-spring. The hairspring is a spiral, and none of its convolutions are concentric with the axis of the balance-wheel, and this eccentricity of the spring brings or throws the center of its weight out of or away from the axis of the balancewhecl and produces the lack of poise in the spring. This lack of poise will produce a variation in the rate of the watch or the amount of time which it gains or loses when running in opposite vertical positions, which will be greater or less according to the length of are through which the balance-wheel swings or vibrates. I have discovered that this defect in watches may be overcome by applying a. small weight or weights to the hairs iring in such positions that the weight or weights will poise the spring and bring its center of weight almost or quite coincident with the axis of the balance-wheel.

flheiiwention consists in the combination, with thchair-spring of a watch or cloclc,of one or more weigh is applied thereto for poising the spring.

The invention also consists in the combina- -tion,with the hair-spring of a watch or clock,

In the accompanying drawings, Figure 1 represents a balance-wheel and hair-spring upon an enlarged scale,and having my invention applied thereto; and Fig. 2 is a trans verse section of a convolution of the spring and a weight applied thereto upon a still more enlarged scale.

Similar letters of reference designate corresponding parts in both figures.

A designates the shaft or arbor of the balance-wheel B, and a designates a collar or collet fixed on the shaft or arbor, and in which is secured the inner end of the hair-spring O. The outer end of the hair-spring C is fixed in the post I) in the usual manner.

It will be readily understood that, inasmuch as the spring is a spiral, no portions of its convolutions are concentric with the axis of the arbor A of the balance-wheel B, and consequently the center of weight of the spring is never coincident with said axis,and the spring is to that extent out of poise.

To poise the spring I apply thereto one or more weights. These I prefer to make adj ust able, and the weight here shown to illustrate myinvcntion consists of a U-shaped clasp, c, straddling the spring, as shown best in Fig. 2, and having its ends bent inward slightly, as shown at Fig.2, in order to secure it on the sp ri n The weights c may be of gold, platinum, or other suitable metal, and one or more of them may be placed on any desired convolution or eonvolutions of the spring. I prefer to make the weights adj nstable on the convolutions of the spring, as they may then be readily shifted to the desired position.

The proper position of the weights may be determined approximately by experiment, and where exact accuracy is desired the watch or clock can be tested, and the proper position of the weights determined accurately.

By my invention I effect the poising of hairsprings at a very small expense and obviate the dilliculty heretofore inherent in them, and I am enabled to adjust watches for position in much less time at much less expense than heretofore.

lVhat I claim as my invention, and desire to secure by Letters Patent, is

1. The combination, with the hair-spring of watch or clock, of one or more poising-w eights, re

a watch or clock, of one or more weights apeach consisting of a U'shaped metal clasp plied thereto for poising the spring, substanstraddling the spring and having its ends bent tially as herein described. inward to secure it thereon, substantially as 5 2. The combination, with the hair-spring of I herein described.

a watch or clock, of one or more weights applied to and adjustable upon the spring for I Witnesses:

poising it, substantially as herein described. O. HALL,

3. The combination,with the hair-spring of a FREDK. HAYNES.

THEOPHILUS GRIBI. 

